Remove SQL GET request from UpdateAmphoraComputeId
Remove SQL GET request from UpdateAmphoraComputeId

"UpdateAmphoraComputeId" task actually return an object and perform
a SQL request not used by any taskflow.
"UpdateAmphoraComputeId" task usage in amphora_flows doesn't
provides anything. Hence SQL request and return value can be avoided.

Change-Id: I93eca3193435fd59fc2d73fc1d820ae51fde3e03

openstack/octavia,openstack/octavia,openstack/octavia